One common treatment for male erectile dysfunction includes the implantation of a penile implant device. One type of penile implant device includes a pair of cylindrical prostheses that are implanted into the corpus cavernosae of the penis. Typically, the cylindrical prostheses or cylinders are inflatable and are connected to a fluid-filled reservoir through a pump and valve assembly. With one such type of system, one tube extends from each of the two cylindrical prostheses and connects to the pump, and one tube connects the pump to the reservoir. The pump is typically surgically implanted into the scrotum of the patient and the reservoir is implanted in the abdomen, with the tubes fluidly connecting the components. To activate the penile implant device, the patient actuates the pump using one of a variety of methods that cause fluid to be transferred from the reservoir through the pump and into the cylindrical prostheses. This results in the inflation of the prostheses and produces rigidity for a normal erection. Then, when the patient desires to deflate the prostheses, a valve assembly within the pump is actuated in a manner such that the fluid in the prostheses is released back into the reservoir. This deflation returns the penis to a flaccid state.
In three-piece systems such as those described above, the reservoir can sometimes be unintentionally compressed by bending or other pressure in the abdomen, which can lead to an inadvertent and undesirable spontaneous inflation of the cylinders. This can occur because many pump designs are not intended to prevent movement of fluid from the reservoir to the cylinders when the pump is subjected to pressurized fluid from a compressed reservoir. For one example, a pump that includes various poppets, springs, and valve seats can provide for fluid-tight seals for prevention of certain fluid movement under normal reservoir pressures. However, these same fluid-tight seals may be broken or opened when subjected to increased external pressure from the reservoir, thereby allowing fluid to move to and inflate the cylinders. This cylinder inflation can be embarrassing and uncomfortable for the user.
With a three-piece system, the implantation of the three distinct parts of the system (i.e., reservoir, pump, and cylinders) in different parts of the body is typically more invasive to the patient than a system that requires accessing fewer areas of the body. Another system that may be used that typically requires less invasive surgical access can be referred to as a two-piece system. A two-piece system typically differs from a three-piece system in that it does not include a reservoir that is separate from the pump. One such type of system is described, for example, in U.S. Pat. Nos. 4,651,721; 4,895,139; 5,010,882; 5,048,510; and 5,263,981, the entire contents of which are incorporated herein by reference. In these types of systems, the pump itself stores the fluid of the system, thereby also functioning as a reservoir. The pump of this type of system is typically implanted in the scrotum and directly connected to cylinders implanted in the corpus cavernosae of the penis. These systems often involve steps such as manipulating a pump body to activate the pump, then repeatedly squeezing and releasing the pump to transfer fluid to the cylinders. The pump can be squeezed as many times as necessary to achieve the desired firmness of the cylinders. Depending on the system, this can take a significant period of time and may require more repetitive squeezing and releasing cycles than is desirable or convenient for the user.
With both two-piece and three-piece systems, due to the positioning of the pieces of each system relative to each other and the type of pumping mechanism provided with the system, some systems require relatively significant manipulation by the user to transfer fluid to and from the cylindrical prostheses. Such manipulation may be either time-consuming or difficult, particularly for users who have problems with dexterity or complicated instructions. Thus, it is desirable to provide an inflatable prosthetic penile device or system that is easy to activate for cylinder inflation and deflation, and that minimizes or eliminates the chances of spontaneous cylinder inflation.